{"common":{"save":0,"post_id":"6069","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"5201","mon_id":"1158767","chapter_id":"1158770","post_id":"6069","question":"<p>H&atilde;y li\u1ec7t k&ecirc; c&aacute;c ph\u1ea7n t\u1eed c\u1ee7a t\u1eadp&nbsp;<span class=\"math-tex\">$X=\\{ x\\in\\mathbb{R},2x^2-5x+3=0\\}$<\/span>.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$X=\\{ 0\\}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$X=\\{ 1\\}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$X=\\{ \\dfrac{3}{2}\\}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$X=\\{ 1; \\dfrac{3}{2}\\}$<\/span>"],"correct":"4","level":"2","hint":"","answer":"<p>Ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$2x^2-5x+3=0$<\/span>&nbsp;c&oacute; hai nghi\u1ec7m&nbsp;<span class=\"math-tex\">$x=1$<\/span>&nbsp;v&agrave;&nbsp;<span class=\"math-tex\">$x=\\dfrac{3}{2}$<\/span>&nbsp;(\u0111\u1ec1u th\u1ecfa m&atilde;n&nbsp;<span class=\"math-tex\">$x\\in\\mathbb{R}$<\/span>).<\/p><p>V\u1eady t\u1eadp&nbsp;<span class=\"math-tex\">$X=\\{ x\\in\\mathbb{R},2x^2-5x+3=0\\}$<\/span>&nbsp;<span class=\"math-tex\">$=\\{1;\\dfrac{3}{2}\\}$<\/span><\/p><p>\u0110&aacute;p &aacute;n&nbsp;<span style=\"color:#16a085;\"><strong>D.<\/strong>&nbsp;<span class=\"math-tex\">$X=\\{ 1; \\dfrac{3}{2}\\}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-08-28 04:25:52","option_type":"math","len":0},{"id":"5203","mon_id":"1158767","chapter_id":"1158770","post_id":"6069","question":"<p>H&atilde;y li\u1ec7t k&ecirc; c&aacute;c ph\u1ea7n t\u1eed c\u1ee7a t\u1eadp&nbsp;<span class=\"math-tex\">$X=\\{ x\\in \\mathbb{N}\\space | \\space (x+2)(2x^2-5x+3)=0\\}$<\/span>.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$X=\\{ -2;1\\}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$X=\\{ 1\\}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$X=\\{ -2;1;\\dfrac{3}{2}\\}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$X=\\{ 1;\\dfrac{3}{2} \\}$<\/span>"],"correct":"2","level":"2","hint":"","answer":"<p>Ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$ (x+2)(2x^2-5x+3)=0$<\/span>&nbsp;c&oacute; ba nghi\u1ec7m l&agrave;&nbsp;<span class=\"math-tex\">$x =-2$<\/span>&nbsp;,&nbsp;<span class=\"math-tex\">$x =1$<\/span>&nbsp;,&nbsp;<span class=\"math-tex\">$x =\\dfrac{3}{2}$<\/span><\/p><p>V&igrave;&nbsp;<span class=\"math-tex\">$1\\in\\mathbb{N}$<\/span>,&nbsp;<span class=\"math-tex\">$-2\\notin \\mathbb{N}$<\/span>,&nbsp;<span class=\"math-tex\">$\\dfrac{3}{2}\\notin \\mathbb{N}$<\/span>&nbsp;n&ecirc;n t\u1eadp&nbsp;<span class=\"math-tex\">$X=\\{ 1 \\}$<\/span><\/p><p>\u0110&aacute;p &aacute;n l&agrave;&nbsp;&nbsp;<span style=\"color:#16a085;\"><strong>B.<\/strong>&nbsp;<span class=\"math-tex\">$X=\\{ 1\\}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-08-28 04:35:46","option_type":"math","len":0},{"id":"5204","mon_id":"1158767","chapter_id":"1158770","post_id":"6069","question":"<p>H&atilde;y li\u1ec7t k&ecirc; c&aacute;c ph\u1ea7n t\u1eed c\u1ee7a t\u1eadp h\u1ee3p&nbsp;<span class=\"math-tex\">$X=\\{ x\\in \\mathbb{Q} \\space | \\space x^4-6x^2+8=0\\}$<\/span>.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$X=\\{-2;2\\}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$X=\\{-\\sqrt{2};\\sqrt{2}\\}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$X=\\{\\sqrt{2};2\\}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$X=\\{-2;-\\sqrt{2};\\sqrt{2};2\\}$<\/span>"],"correct":"1","level":"2","hint":"","answer":"<p>Gi\u1ea3i ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$x^4-6x^2+8=0$<\/span><\/p><p>\u0110\u1eb7t&nbsp;<span class=\"math-tex\">$t=x^2\\space(t\\ge0)$<\/span>, ph\u01b0\u01a1ng tr&igrave;nh \u0111&atilde; cho tr\u1edf th&agrave;nh&nbsp;<span class=\"math-tex\">$t^2-6t+8=0$<\/span><\/p><p>Ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$t^2-6t+8=0$<\/span>&nbsp;c&oacute; hai nghi\u1ec7m l&agrave; t = 2 v&agrave; t = 4 (\u0111\u1ec1u th\u1ecfa \u0111i\u1ec1u ki\u1ec7n&nbsp;<span class=\"math-tex\">$t\\ge0$<\/span>)<\/p><p>V\u1edbi t = 2 th&igrave;&nbsp;<span class=\"math-tex\">$x^2=2$<\/span>, suy ra&nbsp;<span class=\"math-tex\">$x=\\sqrt{2}$<\/span>&nbsp;ho\u1eb7c&nbsp;<span class=\"math-tex\">$x=-\\sqrt{2}$<\/span>&nbsp;<\/p><p>V\u1edbi&nbsp;t = 4 th&igrave;&nbsp;<span class=\"math-tex\">$x^2=4$<\/span>, suy ra&nbsp;<span class=\"math-tex\">$x=2$<\/span>&nbsp;ho\u1eb7c&nbsp;<span class=\"math-tex\">$x=-2$<\/span>&nbsp;<\/p><p>Suy ra ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$x^4-6x^2+8=0$<\/span>&nbsp;c&oacute; 4 nghi\u1ec7m l&agrave;&nbsp;<span class=\"math-tex\">$-2;-\\sqrt{2};\\sqrt{2};2$<\/span>.<\/p><p>V&igrave;&nbsp;<span class=\"math-tex\">$-2;2\\in\\mathbb{Q} $<\/span>&nbsp;v&agrave;&nbsp;<span class=\"math-tex\">$-\\sqrt{2};\\sqrt{2}\\notin \\mathbb{Q}$<\/span>&nbsp;n&ecirc;n&nbsp;&nbsp;<span class=\"math-tex\">$X=\\{-2;2\\}$<\/span><\/p><p>\u0110&aacute;p &aacute;n l&agrave;&nbsp;<span style=\"color:#16a085;\"><strong>A.<\/strong>&nbsp;<span class=\"math-tex\">$X=\\{-2;2\\}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-08-28 04:37:01","option_type":"math","len":0}]}